Week 9 Ch. 47

Question 1

Mechanoreceptor stimuli

Answer 1

mechanical compression/ stretching

Question 1

Thermoreceptor stimuli

Answer 1

Temperature
*specific neurons dedicated to hot or cold

Question 2

Nociceptor stimuli

Answer 2

Physical or chemical damage (pain)

Question 3

Electromagnetic receptor stimuli

Answer 3

Light on retina of eye

Question 4

Chemoreceptor stimuli (5 examples)

Answer 4

1. taste
2. smell
3. oxygen level in arterial blood
4. Osmolality of body fluids
5. CO2 concentration

Question 5

Each receptor is sensitive to ____ stimuli

Answer 5

1 type of stimuli

Question 6

Labeled line principle

Answer 6

Specificity of nerve fibers transmitting one modality of sensation

Each nerve tract terminates at a specific point in nervous sytem

Question 7

When a stimuli excites a receptor the effect is:

Answer 7

to change the membrane electrical potential (allows action potential)

Question 8

Four way to excite receptors (and open ion channels)

Answer 8

1. Mechanical deformation of receptor
2. Application of Chemical to membrane (ligand gated)
   3.Change in temp (alters permeability)
3. Electromagnetic (light changes receptor membrane)

Question 9

Max amplitude of receptor potentials

Answer 9

100 mV (-70 to +30)

Question 10

Pacinian corpuscle facilitiates

Answer 10

compression response

Question 11

Pancinian corpuscle MOA

Answer 11

compression anywhere on capsule layers will elongate, deform, or indent central fiber

Question 12

Deformation of pancinian copuscle causes

Answer 12

Sodium channels to open –> action potential at nodes of ranvier

Question 13

Strength of stimuli in pacinian corpuscle and reasoning

Answer 13

rapid increase in amplitude, then decrease in amplitude as stimulus strength increases

allows receptor to be very sensitive to weak stimuli but only max out with max stimuli

Question 14

Receptor adaptation

Answer 14

all sensory receptors adapt partially or completely to constant stimulus

Pain receptors may never fully adapt

Question 15

Pacinian corpuscle adaptation

Answer 15

Fluid is redistributed to receptor potential is no longer disturbed

(Coin lab)

Question 16

Rapidly adapting receptors (3)

Answer 16

1. free nerve endings
2. Muscle spindle
3. Tactile hair

*aka rate, movement or phasic receptors

Question 17

Rapidly adapting receptors only react when

Answer 17

stimulus strength changes

Question 18

Tonic receptors role

Answer 18

keep brain informed of the bodies relationship in space at all times

Question 19

Tonic receptor examples (4)

Answer 19

1. Baroreceptors
2. Pain receptors
3. Macula receptors
4. Chemoreceptors

Question 20

What affects speed of signal transmission

Answer 20

Myelinated = faster
Larger diameter = faster

Question 21

Type A fibers
(characteristics and subdivisions)

Answer 21

-myelinated
-Subdivided into alpha, beta, gamma delta

Question 22

Type C fibers
(characteristics and location)

Answer 22

-Small, unmyelinated (low velocity)
-1/2 sensory fibers in peripheral and postganglionic autonomic

Question 23

Spatial summation

Answer 23

increasing signal strength d/t increasing NUMBER of nerve fibers

Question 24

Temporal summation

Answer 24

increasing signal strength d/t increasing FREQUENCY of nerve impulses on each fiber

AP after AP after AP after AP = brain knows a lot is going on

Question 25

Neuronal Pools

Answer 25

spacial division of neurons dedicated to similar function

Question 26

Facilitating of neurons

Answer 26

moves toward + but not causing AP

Question 27

Neurons reaching threshold =

Answer 27

firing

Question 28

Facilitated zone has (proportion of axon terminals)

Answer 28

fewer axon terminals

Question 29

Discharge zone has (proportion of axon terminals)

Answer 29

many more axon terminals/synapses (easier to reach AP)

Question 30

Divergence of neurons - how do them amplify?

Answer 30

1. Amplifies: signal spreads to increasing number of neursons
2. Mulitple tracts: signal transmitted in different directions - spread the message

Question 31

Divergence of neurons - multiple tracts

Answer 31

Signal transmitted in different directions - spread the message

Question 32

How does Divergence excite nerve fibers (2)?

Answer 32

1. Amplifies signal
2. Signal transmitted through multiple tracts

Question 33

Convergence (2)

Answer 33

1. signals from multiple neurons to the same neuron
2. Input to single neuron from multiple others

Question 34

Reciprocal Inhibition Circuit

Answer 34

Outward signals can be excitatory in one direction and inhibitory in another direction

Question 35

Example of reciprocal inhibition circuit

Answer 35

Walking: excites muscles on front of leg, inhibits muscles on back of leg

Question 36

Afterdischarge

Answer 36

long acting synaptic transmitters involved continue to fire so long as potential lasts

prolonged output

Question 37

Reverberatory and example

Answer 37

positive feedback within neuronal circuit to re-excite

ex. respiratory centers of medulla and pons never fatigue enough to stop

Question 38

Intrinsic neuronal excitability and examples

Answer 38

membrane potentials rise above threshold. “Carrier wave system”

don’t cause signal, but control level of intensity

ex. tone, iris, HR

Question 39

Inhibitory circuits

Answer 39

Keep things ‘off’ unless there is enough to turn it on

Question 40

Synaptic fatigue occurs when _____ and causes_____

Answer 40

occurs with prolonged excitation, causes transmission to become weaker

Question 41

Short term overuse of synapse causes

Answer 41

decreased sensitivity

Question 42

short term underuse of synapse causes

Answer 42

increased sensitivity

Question 43

Long term synaptic fatigue causes

Answer 43

change in the number of receptor proteins